Because of how effectively exogenous ketones can reduce hunger for those in ketosis, pay attention to the cues your body gives you. It’s possible to extend your fasts longer than necessary because of a decreased appetite cue. While those who have some weight to lose might be tempted to think this is a favorable side effect, there is a difference between fasting and starving for nutrients. Make sure to get enough food to support your activities and maintain your muscle mass.
Many of us avoid foods like processed meats and cheeses or salted nuts because of their high sodium content. However, processed carbohydrate sources can have equal or higher amounts of sodium per serving. An ounce of salted pretzels[3] has over four times as much sodium as an ounce of salted peanuts[4]. Just because we can’t taste the sodium doesn’t mean it isn’t in there. Flavors from other ingredients like sugar and spices can make it difficult to identify salt as a dominant flavor.
I interviewed Dr. Brianna Stubbs, a ketone researcher with a Ph.D. in Metabolic Physiology from the University of Oxford who is now Research Lead at HVMN, specializing in developing ketone esters. She told me that in terms of science on the ketone salts and their effect on physical performance, one of the most-cited benefits of ketone salts, the scientific studies that have been done show at best no effect on physical performance and that, currently, there is no peer-reviewed scientific research on the ketone salt products on the market.

In a keto-adapted individual where ketone metabolism is brisk with up to 100 grams or more being oxidized (i.e., ‘burned for energy’) daily, the small amount lost in breath and urine as acetone is minor. But because this breakdown occurs spontaneously without needing the help of enzymes, it also happens to AcAc in a stored beverage or food (even in an air-tight container), making the shelf-life of AcAc-containing products problematic. Thus all current ketone supplements consist of BOHB in some form rather than the naturally occurring mix of BOHB and AcAc produced by the liver.

If the color is close to the original beige of the test strip, it means there are few if any ketones in your urine and you’ll need to make some dietary tweaks. This may include eating less fat. That’s because if you have doubled down on the healthy fats your body may be rebelling. One way to tell is if you are constipated. If you think this is the case, ratchet back the fats by 50% and see if it makes a difference.
After a few days of fasting, or of drastically reduced carbohydrate consumption (below 50 g/day), glucose reserves become insufficient both for normal fat oxidation via the supply of oxaloacetate in the Krebs cycle (which gave origin to the phrase ‘fat burns in the flame of carbohydrate') and for the supply of glucose to the central nervous system (CNS).4

Our bodies are produce three types of ketone bodies for fuel: beta-hydroxybutyrate (BHB), acetoacetate (AcAc), and acetone. Each is used by the body differently. Acetone is the least abundant, produced in much smaller amounts, and is usually exhaled through the lungs rather than being used as fuel.3 Acetoacetate is part of the metabolic pathway whereby humans make and use ketones, but it tends to be found in the blood at lower levels than BHB.

It’s not clear that the Weir coefficients used to estimate EE are relevant for someone in ketosis, let alone someone ingesting exogenous BHB. (The Weir formula states that EE is approximated by 3.94 * VO2 + 1.11 * VCO2, where VO2 and VCO2 are measured in L/min; 3.94 and 1.11 are the Weir coefficients, and they are derived by tabulating the stoichiometry of lipid synthesis and oxidation of fat and glucose and calculating the amount of oxygen consumed and carbon dioxide generated.) While this doesn’t impact the main observation—less oxygen was consumed with higher ketones—it does impact the estimation of EE and substrate use.
Ketogenesis is the metabolism of fatty acids by β-oxidation. 4 This process gives acetyl CoA which then leads to β-hydroxy-β-methyglutaryl-CoA (HMG-CoA) as seen below5. HMG-CoA converts into Acetoacetone which can switch back and forth to BHB. Acetoacetone to Acetone conversion is irreversible (on the left below). Acetoacetate and BHB (via acetoacetate) are used to produce energy when converted back into acetyl-CoA within a cell’s mitochondria whilst Acetone is excreted in the breath and urine.4

Animal research findings report that BHB supplementation also enhances oxygen utilization, especially in the central nervous system (CNS).[11] While molecular oxygen is a crucial molecule for health and longevity, too much of it can be potentially toxic and speed the effects of aging in tissues throughout the body.Therefore, using a BHB supplement can effectively mitigate the toxic buildup of molecular oxygen, particularly in the CNS/brain.

I’m already following a ketogenic diet and have been fat adapted for about 3 months. Since I’m already in ketosis would this product help me or hinder my fat loss? My thought is that if I’m already in a fat burning state and then I take exogenous ketones does my body stop burning my fat to burn the ingested ketones like taking a break or does the product enhance the fat burning that is already taking place?
Ketone Bodies are then used by tissues as a source of energy3 through a pathway that leads to formation from β-hydroxybutyrate of two molecules of acetyl CoA, which are used finally in the Krebs cycle. It is interesting to note that the KBs are able to produce more energy compared with glucose because of the metabolic effects of ketosis—the high chemical potential of 3-β-hydroxybutyrate leads to an increase in the ΔG0 of ATP hydrolysis.3

This molecule is quite essential if you are using your own fat for fuel, or taking BHB as an exogenous ketone supplement to increase energy production — essentially to be in nutritional ketosis. If you’re not certain about what ketones are or what nutritional ketosis is, you should back up a little bit and read more about that on my company site, Perfect Keto.

There is one viable explanation for consuming ketones. If you're in a calorie or carb-restricted state, then maybe during a workout it would make sense. But even then, that really only applies to endurance activities, since it has more to do with enhancing aerobic performance (where oxygen is required), than it does with enhancing high-intensity efforts (where it's not).
As stated above, there appears to be a difference between supplemental and dietary calcium intake, which can be important to keep in mind. One study found aggregate calcium intakes above 1400 mg per day (from dietary and supplemental intake combined) to be associated with higher death rates, cardiovascular disease, and ischemic heart disease in women[15]. A 2014 meta-analysis found an association between dietary calcium intake and cardiovascular mortality[16]. The meta-analysis actually found a u-shaped relationship, where dietary calcium intakes that were both lower and greater than 800 mg/day were gradually associated with increased risk of cardiovascular mortality.
I’m just getting back into an active lifestyle after being sedentary for a few years.. Rough start I must admit but I’m focused.. Objective is to lose 80lbs. I’ve previously had my body in ketosis when I was dieting and working out so I can attest to the benefits I’ve felt before.. Now that I see Exogenous Ketones are available, I’m wondering if it’s recommended to start taking them to help jumpstart my body into ketosis since that is the goal for burning fat…
Neuroprotection: As humans age, the brain becomes more susceptible to neurodegeneration and subsequent conditions such as Alzheimer’s and Parkinson’s disease. Exogenous ketone supplementation appears to ameliorate the typical decline in cognitive function that comes with aging. The likely mechanism for this neuroprotective property is that ketone bodies reduce the inflammation and hyperexcitability that is normally exhibited as glucose metabolism declines in the brain.18, 19
The current recommendation for magnesium is 310-320 mg for adult women and 400-420 mg for adult men. Magnesium deficiencies are common; 2005-2006 data indicates that the majority of Americans’ dietary magnesium intake was less than the Estimated Average Requirement (EAR) for the respective age groups[25]. The EAR for a nutrient is about 20% LESS than the RDA. Current data on magnesium intake and deficiency in the US is not readily available, as magnesium testing is not part of routine electrolyte testing in hospitals and clinics[26].
That’s exactly what ketones do: inhibit lipolysis, the breakdown of body fat into triglycerides and free fatty acids for burning. In normal conditions where ketones are produced endogenously, this is expected and beneficial. If homemade ketones increased lipolysis, you’d end up with ketoacidosis. You’d make ketones which released more body fat which got turned into more ketones which released more body fat which became more ketones. And on and on. It simply wouldn’t stop.

The ketone esters are, hands-down, the worst tasting compounds I have ever put in my body. The world’s worst scotch tastes like spring water compared to these things. The first time I tried 50 mL of BHB monoester, I failed to mix it with anything (Dom warned me, but I was too eager to try them to actually read his instructions). Strategic error. It tasted as I imagine jet fuel would taste. I thought I was going to go blind. I didn’t stop gagging for 10 minutes. (I did this before an early morning bike ride, and I was gagging so loudly in the kitchen that I woke up my wife, who was still sleeping in our bedroom.) The taste of the AcAc di-ester is at least masked by the fact that Dom was able to put it into capsules. But they are still categorically horrible. The salts are definitely better, but despite experimenting with them for months, I was unable to consistently ingest them without experiencing GI side-effects; often I was fine, but enough times I was not, which left me concluding that I still needed to work out the kinks. From my discussions with others using the BHB salts, it seems I have a particularly sensitive GI system.

Affiliate Disclosure: There are links on this site that can be defined as affiliate links. This means that I may receive a small commission (at no cost to you) if you purchase something when clicking on the links that take you through to a different website. By clicking on the links, you are in no way obligated to buy.

Medical Disclaimer: The material on this site is provided for informational purposes only and is not medical advice. Always consult your physician before beginning any diet or exercise program.